Of Which Reason Knows Nothing
by PhoenixDowner
Summary: Kairi may have lost someone important, but she isn't alone, and she isn't without hope. And her mysterious dreams just might have a clue as to Sora's whereabouts. (Kairi and Riku friendship, implied SoKai. Set post-Kingdom Hearts III).
1. Chapter 1 - The Dream

Chapter 1 - The Dream

A/N: I'm happy to post the first part of the project Chibiranmaruchan and I collaborated on! They drew the art, and I wrote the fic. Working with them was a lot of fun, and I'm really happy with what we've created. The first chapter I'm posting today, and the second I will post next Friday. I will also be posting this story to AO3 and tumblr if those are your preferred reading spot(s).

* * *

Facing Sora's mother was one of the hardest things Kairi had ever done.

Knocking on the door to Sora's house had required all of her courage as it was. The cheerful welcome sign hanging on it, with its blue letters against a sunny yellow background, was downright mocking. What could she even say? She wasn't welcome here. It was her fault Sora was gone; her fault he—

"Kairi?"

She couldn't even look his mother in the eye. Her throat was dry and all of her carefully planned words fled her mind.

All that came out was, "I'm sorry." Not that any apology could ever make up for what had happened, for the loss of someone so dear to them both.

"Sweetheart, it wasn't your fault."

Her eyes snapped to his mother's. They were just like his, blue as the sky, only clouded with grief. Seeing them was like a punch in the stomach.

"It was," Kairi said. "It's my fault he's dead."

His mother shook her head. "No. Riku told me what happened. It's because of you that he even lived."

Kairi had to choke back a sob at that, and his mother just wrapped her arms around her. She didn't resist. She didn't have the energy to anymore.

"I miss him so much," she said as the tears started to stream down her cheeks anyway.

"I do too."

His mother invited her in after that, for tea and cookies. It actually helped a little, being near things that reminded her of him. Like a part of his soul still lingered on. It helped to tell stories about him, too. To listen to his mother's stories.

"When he came home the night before you two and Riku set off," she said, stirring the sugar and milk into her tea, "I knew something special had happened."

Kairi perked up. "Oh?"

"He couldn't stop smiling. Couldn't focus on anything, especially not his dinner. Just had this big dreamy grin on his face with a faraway look in his eyes as he spilled his rice all over his lap. I figured it had something to do with you."

Kairi smiled a little. "It did." She thought of how he'd looked at her after they'd shared the paopu fruit and felt all warm inside. "He has such a beautiful smile."

"That he does."

They sipped their tea and nibbled on their cookies and kept sharing stories about him. But the shadows outside were growing long now, and Kairi needed to get home for dinner soon.

"Before you go," his mother said, "would you like to see his room?"

Kairi's heart pounded. "Is that… is that okay?"

"Of course. I thought… maybe, if it helps you, you can look at his things."

She nodded. "Okay."

One by one her feet took her up the stairs, each step feeling heavier than the last, till the door to his bedroom was right in front of her.

Maybe this wasn't such a good idea. Maybe it would be better to—

"It's okay. You can go in."

His room hadn't really changed all that much since she'd last been here. The floor was still cluttered with stuff, old toys and clothes and knick-knacks, as he hadn't been home long between his return and his Mark of Mastery exam. But despite that, it was well dusted, and if she didn't know any better, she would expect him to come bursting through the door any second now.

One of his hoodies was strewn across his bed, the red and black one, and she couldn't help herself. She walked over and picked it up, then hesitated and looked back towards his mother for permission.

"Would it be okay… if I borrowed this, for now?"

"Of course. He'd want you to have it."

Kairi nodded and pulled it over her head. It still smelled like him, and wearing it felt like he was giving her a hug.

His mother gave her an understanding look. "I'll be downstairs when you're ready. Take all the time you need."

Kairi couldn't bring herself to sit on his bed, but she did look around his room a little. Resting on his bedside table was a letter – her letter. She picked it up, mouthing the words as she read along. She remembered how her hand had flown across the paper, the words spilling out of her heart as her memories of him had returned.

"Starts with an 'S,'" she murmured as the page in front of her blurred. His expression of pure joy as he ran through the water popped into her head. Would he still have smiled if he knew the fate that awaited him? That only a few months later, he'd be dead because of her?

She set the letter back down. In their final moments together, he'd smiled much like he'd smiled that day, and she had to wipe her eyes. Even the happy memories were bittersweet now. But something told her he wouldn't want her to be sad, and so she did her best to remember the good things.

After returning home, dinner went by in a blur. Her appetite still hadn't recovered, and she could only pick at the delicious food her mother had made, stir fry with pineapples and paopu fruit. The paopu fruit reminded her of Sora, of the cave drawing, of the special moment they'd shared as they'd fed each other the fruit. Not even meals were safe from her memories.

Going to bed was a struggle, too. When she wasn't lying awake for hours on end, thinking about what had happened, she was having nightmares about it instead. A sharp pain in her back as Xehanort struck the killing blow, over and over again. Sora slipping right through her fingers and falling into the abyss. No matter what he did, no matter what she did, they could never reach each other. She always woke up, alone, with tears streaking her cheeks.

But with Sora's hoodie on, things felt a little better. She felt a little closer to him. She sent Riku a quick text, then Xion and Naminé, before putting her Gummiphone back on the bedside table.

Maybe tonight she'd finally be able to sleep.

* * *

Neon lights, flashing colors. An enormous city with skyscrapers pointing towards the moon, trying to reach the heavens but getting pulled back down to earth. Water on the ground in puddles as raindrops splashed into them, disturbing the surface of the water, reflecting the surroundings like a mirror.

Kairi had never seen this place before. It wasn't The World That Never Was – the buildings didn't match. This was somewhere new, somewhere different.

White paint on the ground. Lots of lines running across the street. Big billboards running dozens of different ads at the same time. Cars with bright lights, too bright in the dark. The sky a strange shade of purple with ominous black clouds. A big white tower with the numbers 104 in neon red letters.

She glanced at one of the puddles nearby. A face with blue eyes and spiky brown hair stared back.

Her eyes flew open. "Sora?"

But the dream was over already. What was that place? A big city… a building with the numbers 104… and Sora, somehow. In some place she'd never been before.

Could it be—

No. It was better not to hope. Better not to get her hopes up. And yet… all of her past dreams about him had just been repeating the same things over and over again. This was new.

She grabbed her Gummiphone and made as many notes as possible so she wouldn't forget her dream, then rolled over and went back to sleep.

When she woke up the next morning, she opened her phone to see what it said:

104 Building

Puddles

Sora

Really? That was really all she had written? Curse her sleepy brain for not being thorough. Sighing, she pulled up her chat with Riku. Time to arrange a meeting with him.

* * *

As the mayor's daughter, Kairi's house was up on a hill a little ways away from everyone else's houses. To reach the street where Riku's house was, she hopped on her bike. The wind whistled through her ears as she descended the hill, reminding her of all the times she'd raced down this very hill with Sora and Riku. The roads on Destiny Islands were mostly dirt ones, and it was quite the bumpy ride.

Riku's house looked much like the other houses on Destiny Islands did, but it was nonetheless charming, with its red brick roof and cute shuttered windows. As she approached and parked her bike (no need to worry about locks, no one really stole stuff from each other around here), she noticed smoke was coming out of the chimney. Maybe his mother was cooking something delicious for breakfast.

After a quick knock on the door, Riku invited her in. She removed her shoes and arranged them neatly, then stepped up into the house.

"Sorry for intruding!" she called in the customary way. No one actually thought you were intruding when you visited, but it was the height of bad manners not to say the little phrase.

"Welcome to our home," his mother called back from the kitchen. After exchanging pleasantries, Kairi gave his mother a thank you gift for allowing her to visit, macarons in a nice box with a red bow from the bakery.

Riku led her into the living room after that, and they took a seat on the couch. He poured them both some green tea, then settled back and said, "So, you said there was something you wanted to talk about?"

"Riku, do you know what the numbers 104 mean?"

He frowned. "104?"

"Yes. I saw them in a dream."

She explained as much of the dream as she could remember – the building with 104 and the puddle with Sora's reflection in it. The other details were hazy, but she remembered thinking she hadn't been there before, and she told Riku as much.

"So, a place you don't know. These weird numbers. And Sora. You think it might be a clue as to where he is right now?"

She nodded. "That's exactly what I was thinking, But I thought… maybe… I was just grasping at straws."

"Because you want to see him again."

She didn't say anything. Riku was right on the munny, as always.

"Trust me, I know the feeling," he said with a sigh. "I keep hoping and then wondering if it's just wishful thinking. But this, this sounds like an actual lead."

"What makes you think that?"

She had to hear it from someone else. She couldn't trust her own heart to be honest with her anymore.

"Well, for one, you said it's somewhere you've never been before. Your nightmares were always places you've already been, right?"

She nodded.

"And you saw that building with a very specific number. Why would you remember a detail like that?"

"Well… the four at the end stuck with me."

While residents of Radiant Garden considered the number thirteen unlucky, four was the number of death on Destiny Islands. The hospital didn't have a fourth floor. The numbering went from three on the third floor to five on what should've been the fourth floor. The school didn't have a fourth floor either. So to see it on a building like that when she knew Sora was—

"You think you saw him in the afterlife, don't you?" Riku said.

She nodded again. "It's the only explanation I can think of. But how is that even possible? I thought that once you're dead, that's it. You cross over whatever barrier there is between the Realm of the Living and the Realm of the Dead. No more contact with the people you've left behind."

He shrugged. "If our journeys have taught me anything, it's that there's a lot I don't know about how reality works. But one thing I do know is that if anything can last beyond death, it's the bond you and Sora share."

Tears pricked her eyes. Why was she always on the verge of crying now?

Riku awkwardly patted her head. He was trying, he was really trying, and that made her cry even harder.

"Hey, we'll figure something out," he said. "You and Sora are both too stubborn to let each other go. And luckily for you both, I'm too stubborn to let either of you go."

She laughed through her tears at that. Sora might be gone, but at least she still had Riku. At least she still had the rest of her friends. Together, they'd find a way to bring Sora back.

* * *

A/N: Thanks for reading! Check back next week for Chapter 2!


	2. Chapter 2 - This Time, I'll

Chapter 2 - This Time, I'll...

That night, Kairi wore Sora's hoodie to bed again. Maybe it wasn't related to her dream at all, but it couldn't hurt to wear it, just in case there was some sort of connection.

As her eyes flickered shut, she murmured, "Sora, if you're out there… if you're trying to reach me… I'm listening."

Neon lights, flashing colors. An enormous city with skyscrapers pointing towards the moon, trying to reach the heavens but getting pulled back down to earth. Water on the ground in puddles as raindrops splashed into them, disturbing the surface of the water, reflecting the surroundings like a mirror.

She was back. She was back in the same place as before.

White paint on the ground. Lots of lines running across the street. Big billboards running dozens of different ads at the same time. Cars with bright lights, too bright in the dark. The sky a strange shade of purple with ominous black clouds. A big white tower with the numbers 104 in neon red letters.

She glanced at one of the puddles nearby. A face with blue eyes and spiky brown hair stared back. Lifting her hand, she gasped at what she saw. It wasn't her hand. It was Sora's, and he was holding a small black pin with a skull-looking emblem on it. He turned it over, and the whole world seemed to go wonky.

"Huh?" He dropped the pin and clutched his head.

"Sora!" she cried, but he couldn't hear her. His Gummiphone buzzed in his pocket, and he pulled it out.

The message said:

Reach 104. You have 60 minutes. Fail, and face erasure.

— The Reapers.

"Huh?!"

He put his phone back in his pocket. Pain shot up his arm, and he winced and looked at his hand again. Engraved into his palm were black numbers with yellow outlines and a red background.

59:49. 59:48. 59:47. They kept changing, kept… going down. Kept decreasing with each passing second. When he looked at the 104 building again, it said YOU HAVE 7 DAYS in big red letters against a black background.

"Sora!"

But the dream was over, and her eyes flew open. Fingers shaking, she grabbed the Gummiphone on her bedside table. The phone rang and rang and rang as her heart raced because of her dream.

"C'mon, Riku, please, please pick up—"

A few moments later, and he did.

"Kairi?" came his familiar voice, if a little groggy. She glanced at the little time display at the top of the screen. A few minutes after six. The video kicked in, and he yawned as he wiped the sleep out of his eyes.

"Riku, I had another dream about him again," she said, unable to hide the excitement in her voice.

Riku perked up immediately at that. "You did? What was it about this time?"

"He was in that city I saw before, only this time there was more." She closed her eyes and pictured it now. The busy crosswalk, the building with 104 written on it, all the colorful lights and sounds. And the red and black numbers carved into his palm. "There was a countdown, on his hand," she added, trying to include as many details as possible.

"A countdown?" Riku repeated, his voice rising.

Her eyes flew open. "Yes. I'm not sure why, but—"

"Kairi, I think I know where he is. I think I know where he is ," Riku said, and his voice had more energy and hope in it than it had since… well, since everything had happened.

She tugged at Sora's hoodie and sat up straighter at that. "W-what? But how?"

"When we were taking our Mark of Mastery exam, he met this guy named Neku. He told me later on that Neku talked to him about a game."

"And?"

"There was a countdown on Neku's hand that was a part of that game."

She thought about this for a moment. "So you think he might be playing the same game as Neku?"

Riku nodded. "Yeah. He said Neku was from this place called Shibuya. If we can find that, we can find him."

This was it, this was their best lead ever since he'd disappeared. She said goodbye to Riku and threw on some clothes. They had to go see Master Yen Sid about this. Their friends all deserved to know.

* * *

Kairi waited with bated breath as Master Yen Sid closed his eyes and stroked his beard. Stealing a quick glance at Riku, she wondered if he was feeling as wound up as she was right now. His face was a calm mask, but then again, he'd never really worn his heart on his sleeve the way she and Sora did.

"So, you are convinced Sora is somewhere called Shibuya, playing some sort of game," Master Yen Sid said.

Kairi nodded. "Yes, Master. I know it may seem a little crazy—"

"On the contrary, where else would a heart go after fading from the Realm of Light? Sora did not die a normal death, and there are legends of the same thing happening to others."

"Really?" Riku asked. "Like who?"

Kairi knew what he was thinking. If it had happened to someone else before, there might be clues as to how to save Sora.

"There was a man who called himself the Master of Masters," Master Yen Sid said. "He had six Keyblade-wielding apprentices, all named after the Seven Deadly Sins. Ava, Luxu, Invi, Gula, Ira, and Aced, with him as their leader: Superbia. Legend has it that instead of dying, he simply faded away, never to be seen or heard from again."

Kairi and Riku both waited to hear more, but it soon became clear that was all.

"That's it? That's all?" Riku said, echoing her thoughts. "This… Master of Masters guy never returned to the Realm of Light?"

"Well, there is more to the story, but it relates to the events of the Keyblade War, and the two of you would be here for days if I were to recount it all to you. I do not think a history lesson is what you want right now. I shared this with you so you would know that the same fate that befell Sora has befallen someone else before, if the legends are to be believed. That was why Mickey tried to warn him against doing what he did, but as the philosophers say, the heart has its reasons of which reason knows nothing."

Master Yen Sid smiled sadly, and Kairi's heart sank. They had warned Sora not to save her and he still did? Why?

"I know it should be him here with Riku instead of me," she said. "But if there's anything I can do to—"

"Incorrect. You are exactly the person who should be here with Riku right now," Master Yen Sid said. "For if Riku is to dive into realms unknown, who better to keep his heart tethered to the Realm of Light than a Princess of Heart?"

"I can do that?" Kairi said.

"You kept Sora tethered to the Realm of Light, did you not?"

"Well, yes, but… that was different, Master. My powers don't work on other people the way they work on Sora, and I'm not really sure why, though I do have a few guesses."

Riku raised an eyebrow but thankfully kept his mouth shut.

"As I said earlier: the heart has its reasons of which reason knows nothing," Master Yen Sid said. "But no matter; in keeping Riku tethered to the Realm of Light as he descends to the depths, you will be helping Sora. Surely you can see how your powers could still be used in this manner."

"I suppose…"

"Have some faith in yourself, Kairi," Riku said. "You kept Sora alive, and that let him save the rest of us. I know you'll be able to pull this off."

Kairi's hand fluttered to her necklace. "But what if I can't? What if I screw up again? I already lost Sora because I was too weak to stop myself from dying. I can't… I can't lose you too, Riku!"

Riku put his hand on her shoulder. "You can do this, I know you can. You're not alone. Together we'll find Sora and bring him back." His expression softened. "And you know how I know that?"

"How?"

"Sora believes in us. He believed he'd find you when you were lost. He never gave up on me after all the crap I pulled. So let's believe in ourselves the way he does."

Riku was right. Even though Kairi had trouble believing in herself, she couldn't deny that Sora believed in her. And she believed in him. She believed in Riku, too. And maybe that would be enough.

"Okay, I'm willing to try," she said, and Master Yen Sid and Riku both nodded.

"We must begin preparations at once," Master Yen Sid said. "There is no time to waste. The sooner we can reach Sora and bring him back to the Realm of Light, the better."

Finally. They finally had something to do besides sit around at home and grieve. Taking action felt so much better than doing nothing.

As she and Riku made preparations, she couldn't help but reflect back on those words she'd told Sora and Riku before. This time, she wasn't just going to protect Sora. This time, she wasn't just going to fight. This time, she was going to act. She was going to be the one searching for Sora for once instead of the other way around.

* * *

The night before the mission, Kairi dreamed of Sora again. He was still in that same city, but he wasn't at the big crosswalk anymore. He was on a side street, fighting some strange-looking creatures Kairi had never seen before. They weren't Heartless or Nobodies, but they did look like large frogs with elaborate red and black tattoos where their legs should've been. And even through the dream, Kairi could sense how the atmosphere surrounding them felt. Her skin crawled and her mood dropped, and she could only imagine how Sora felt fighting them.

When he had destroyed the last of them with his Keyblade, he stumbled against a nearby building, a store with bright red letters. His bangs were stuck to his forehead, and he was breathing hard. How long had he been fighting? How many of those things had he already fought?

But what really drew her attention was when he reached into his pocket and pulled out her lucky charm. Her heart soared at the sight of it. He still had it. He still—

"Why can't I remember you?" he said, and his voice was anguished.

Her heart sank. Sora didn't… remember her?

Why not? What had happened to him? Were all his memories gone?

"Sora?" she said. "Sora, I'm here!"

But he couldn't hear her, and he tucked the charm back into his pocket. "Doesn't matter. Whoever gave this to me has to be someone important to me." He looked right at her and made a guts pose, even though he couldn't see her. "Whoever you are, I'm gonna get home to you, some way, somehow." He smiled, and it was so good to see his smile again. "I promise."

She opened her mouth to reply, but the dream was over, and her eyes flew open. She rolled over onto her side, still wrapped in Sora's hoodie, and huddled beneath her blanket as light poured through the window.

Did Sora really not remember her? Her lower lip trembled at the thought. How could he have forgotten her after everything they'd been through? This was like when she'd forgotten him, and a lump built in her throat when she remembered how awful that had been. The memories slowly slipping away from her. The day she'd forgotten his name. The night she'd forgotten his face. The moment she realized she couldn't hear his voice anymore. All of that came crashing back to her, and her eyes welled up with tears.

But she and Sora had gotten through that, in the end. And his promise did make her feel a little better. Maybe the memories were all scrambled up, but they weren't gone for good. They had to still be in his heart somehow. The bond they shared couldn't be broken that easily.

The important thing was that he was fighting to get back to her. So she would fight to reach him, too. Whatever obstacles they might face, she and Riku would bring him home.

* * *

"You ready?" Kairi asked as she held her hands out to Riku. They were back in Master Yen Sid's study, and everyone else was here too – King Mickey and Donald and Goofy, Terra and Aqua and Ven, Naminé, of course, and Roxas and Xion and Axel. Even Isa was present. Admittedly, that made her feel a little uncomfortable, but at least he had the good sense not to try to talk to her.

"Ready if you are," Riku said with a half-grin. How he was so relaxed about this, she'd never know. Her hands were shaking a little, but when he grabbed a hold of them, a wave of calm washed over her.

"For Sora?"

"For Sora."

Her eyes fluttered shut, and she pictured Sora searching for her in Shibuya. Pictured Riku, pictured his heart.

There. She could see his Station of Awakening now with its stained glass-like panels showing the people that were most important to him. Friends and family and memories spread throughout his heart. Taking a deep breath, she reached out with her light, tethering her heart to his. His memories started flowing through her mind, and she opened her eyes.

"Okay, I'm connected to you now. Whenever you're ready."

He looked around at their friends. "Hey, why the long faces? Don't worry about me. I'll be back here with Sora in no time, you'll see." He looked at Kairi one more time and smiled. "We won't give up on him, because he never gave up on us. And he's helped every person here in this room at one time or another. Now it's time we return the favor."

There was a general chorus of agreement and well-wishing at that. Letting go of one of Kairi's hands, Riku summoned his Keyblade and opened a large portal above them complete with swirling colors and elaborate designs of a bygone age.

"Stay safe, Riku," she said. "See you soon."

And with that a great beam of light shot down and pulled him into the portal. Her hand was now empty, and she rested it over her heart.

"Well?" King Mickey said.

She smiled. "He's okay. I can feel him."

Everyone breathed a collective sigh of relief.

"And… I can feel Sora's heart, too. He may not remember me yet, but I know he will soon."

"That's the magic of the paopu fruit!" Goofy said, then slapped his hands over his mouth as Donald tapped his foot.

"Hey, you weren't supposed to tell everyone that," Donald scolded, and everyone laughed as Kairi blushed. Great, did all their friends know about the paopu fruit? Well, not surprising. Juicy gossip had a way of spreading like wildfire.

"Hey, if the Wayfinders can bring me and Aqua and Terra back together again, imagine how powerful the real thing will be!" Ven pointed out. "Especially because you and Sora—"

"Less teasing, more practicing with your Keyblade," Aqua chided, but she was smiling, and Terra grinned and ruffled his hair. Ven pretended to protest, but it was obvious he liked the hair ruffling and playful scolding.

As the others started up conversations with each other, catching up on how everything had been going since everyone had last seen each other, one person in particular sought Kairi out. Naminé, still holding her sketchpad and pencil but wearing a cute new dress, blue and yellow and white.

"Kairi?"

"Yes Naminé? What is it?"

"I know you're feeling sad about Sora forgetting you, but I doubt those memories are gone for good. Look at Xion," she said, gesturing at their friend, who smiled and waved at them. "We all thought no one would remember her, and yet here she is now. Sora's memories of you will come back, I just know they will."

"Thanks, Naminé. And when Sora finally comes back, he can thank you properly, too."

Naminé smiled, and Kairi went over to talk to Axel and Roxas and Xion some more, then to King Mickey and Donald and Goofy, then lastly to Terra and Aqua and Ven. She had something very important to ask, something she wanted to do as Riku searched for Sora and she kept him tethered to the Realm of Light.

"Master Aqua, please take me on as your apprentice," she pleaded as she bowed low. This was her best shot, her best hope at becoming a better Keyblade wielder after the disaster that had happened at the Keyblade Graveyard.

When she straightened, her throat dry, Aqua was beaming down at her. "I thought you'd never ask."

She clasped her hands and thanked Aqua profusely. Here was an opportunity to get better, to improve, to become a better fighter by the time Sora and Riku returned. She wasn't the weak girl that had gotten kidnapped and killed anymore. She had the heart and will to be strong, and she was going to prove it.

However long it might take, however hard she would have to work, it didn't matter. Someday, she would fight by Sora's side again. Someday, she would be able to spar with Riku and give him a run for his munny. Someday, the three of them would be together again and all would feel right in the worlds.

And someday, she and Sora would finally be able to make good on the promise they'd made. They'd be together every day, and nothing would be able to keep them apart anymore.

For that, she would train and fight for as long as it might take. Now was the time to step forward like she'd said she would. Now was the time to act. The fight was in her hands, and she was ready at long last.

* * *

A/N: Once again, a big thank you to Chibiranmaruchan! They drew the art, and I wrote the fic for this collaboration.

And as always, thank you for reading! Hope you enjoyed!


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